1. Field of the Invention
This invention relates to the preparation of oil-soluble dihydrocarbyl monothiophosphoric acid compositions, and the use of such compositions in lubricants, fuels and greases.
2. Description of the Related Art
U.S. Pat. No. 3,984,448 (Lippsmeier, Oct. 5, 1976) relates to a process for making metal dialkylthiophosphates of the general formula: ##STR4## in which R.sub.1 and R.sub.2 stand for identical or different linear and/or branched alkyl radicals having from 1 to 6 carbon atoms, M stands for a metal cation and n indicates the valence of the metal cation concerned, wherein O,O-dialkylphosphites of the general formula ##STR5## in which R.sub.1 and R.sub.2 have the meanings given hereinabove, are reacted with a compound yielding the metal cation M, in the presence of pulverulent sulfur and one or more organic solvents at elevated temperature.
The organic solvents are selected from alcohols, ethers, aliphatic and aromatic hydrocarbons, and chlorinated saturated or unsaturated hydrocarbons.